New Zealand First in this morning's Herald DigiPoll surged to 3.7 per cent, almost double the level of support it had last week.
With Mr Peters choosing not to stand in an electorate this election, the party needs at least 5 per cent support to win a ticket back to Parliament.
He told the audience of about 50 people that New Zealand First would sit on the opposition benches if it returned to Parliament.
"I have spent my whole political career focused on a need for New Zealand to have one law for all. ... The issue that has concerned me and on which I have never been silent is a developing pattern of laws that says some people have special rights over those of other on the basis of race."
He said New Zealand under National or Labour would continue down the path of "separate development".
He said New Zealand had two flags, had signed up to the UN Declaration of the Rights of Indigenous Peoples, a review looking at making the Treaty of Waitangi the cornerstone of the constitution, and emerging separate sections of the penal and social welfare systems.
"We are not prepared to prop up any government whatever its political hue, however it is cobbled together, that encourages, even celebrates, such a prospect of future divisiveness. For that would be to support the torturous pathway to Zimbabwe," Mr Peters said.
"We are going in to Opposition to use every ounce of our energy to bring sanity to the political system. We have seen separatism and racial division in other countries, and we'll do everything in our power to stop it happening here."
He also said the Emissions Trading System was a waste of space because of the costs it put on the export sector.
He believed in climate change, but the ETS was a tax on people and production.
"NZ First does not subscribe to a 'Wall Street' takeover of the environment' and profiteering out of just one more distortion of market forces."
Instead, he said New Zealand should work to reduce coal use and push alternative sustainable fuels, and targeted research and development.
"The bottom line is that the proposed ETS will incur a very large cost - $2 Billion - that can be much better used to repay debt."
